Group environment Variables:

Rationale:

In many cases the environment settings become so big that they are
difficult to navigate and to change. It has been suggested that it
would be nice if variables could be ordered into "groups" or "blocks",
but it seems difficult to get an agreement what exactly these groupos
should be.

Suggested Implementation:

The following idea attempts to be as little introsive to existing code
as possible, while allowing maximum flexibility at the same time.

Only a single new environment variable, "env_groups" has to be
reserved for the implementation of this feature. It is suggested,
that the "env_" variable prefix gets reserved for this, even though
this is not necessary from the technical point of view.

"env_groups" is intended to hold a list of variable names.

The implementation of the "printenv" command needs to be changed
such that it groups the output according to the names stored in this
list.

Note 1: I think it makes sense to raise errors as shown above for
variables, that are undefined but listed as members of some group.

Note 2: It is trivial to print just a the variables of a specific
group by running for example:

=> printenv ${env_net}

Note 3: If the "Set Environment to Default Values"
feature gets implemented as suggested, it is also
trivial to delete or reset all variables of a group to their built-in
default values by running for example:

=> environment default ${env_net}
=> environment clear ${env_flash}

Additional feature:

It would be nice if variables in each group could be sorted
alphabetically when they are printed using the "printev" command.